1. Field of the Invention
The present invention relates to systems and methods for controlling the interface of digital circuits with other circuitry. More particularly, the present invention relates to apparatus and processes for controlling the voltage levels employed for logic control signals introduced to digital input/output (I/O) circuits.
2. Description of the Related Art
Socket compatible input receivers and output drivers have existed in the prior art. Their capabilities are featured in the "VS500 Standard Cell Library" or the 0.75 mm standard cell library offered by NCR Microelectronics and its associated data books and application notes. To accomplish the voltage sense function, however, the prior art either uses a bandgap reference voltage to determine the voltage level of the supply, or relies on external control input from outside the integrated circuit device.
The Peripheral Component Interconnect (PCI) standard was established by an organization of many members of the industry known as the PCI Special Interest Group (PCISIG). The PCI specification defines two operating voltage regions including the provision of devices switching between the two. That specification does not discuss the capability of dynamically switching between the two regions without any control input as is realized through the present invention.